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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9947d66f5b2a677274f0f29a0f9dd22ded5f68afa5ac9ffde0a6948b693ce02' 
  AND token = 'uGg04q5fP/dR4wOs6fVuvzmTkNzHQSvM6EaMC4GcBEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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