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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6633a766a5be0183788ab3ef51778ae0d1f32c60cfd07f1bfeebd2c4f7b4aa1' 
  AND token = 'iyK4ECZM6pFHZ3lFWMcbCnCRAwGIyDEqcB5sqmBX7Ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}