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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef7fc879e0ac01ced3165b1f9f20c2f1aa51b7c88bddec4e869a385a0b51481f' 
  AND token = 'JoSZf1tZiBeAj+ps/ckRKX+p4oR7uuOk9toadmLGM1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}