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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4930df09a0774038752d2b1365aed49922d59c3f2b10a3a01c0d911bf2c9a21e' 
  AND token = 't44ac2N9c+VrJ+CkArSoam0DZES49OoLdvLQI3aa1QE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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