SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14a2c73a11791762318ddbd65b25b77ec43c41b2e8507304a16035eab0331022' 
  AND token = 'SvAzAq8cTt3CgSIjPqIpVhzPMWM0c9j8VN+YEtQeKog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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