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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1bfffb3a4b58853c9eef580e24074b5dd061aa66b4b469fb078535f60a1b1df' 
  AND token = '5vyVtnYjqRTIEHgRQOiQgLCCamo+iN+lPs3A7ig8SRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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