SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66d082da968f0ed4f48653699980300c2e95112e89d7544b9732488f3bcb5a04' 
  AND token = 'u62tTvhBwO32s0Eb+wy70U6LUQ09dGrVB1A3wz+j/DE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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