SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b51327e0d69edf27fabaae3e92668c2c17eb08991279adf8f32c93d85f0b220f' 
  AND token = 'qfmHpP9ImYRTAg/4k4vCGpVKQVh0Ye2K6fTGdgBYCQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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