SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82fcdc834885746a005770c639ca915418e93631c96301104b922e0486ff1c18' 
  AND token = 'wETVet91RrCzbc81occrBihYcqi2NVpeDvJIEV49iyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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