SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0615727f32ef13d03230a3541824846d2e0694f47edd864ac4de9574b5175389' 
  AND token = 'TZu2uFfK1H0S+l/GNOUkHa4GYJAA9HCGEXIXksCfw9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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