SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2998a129c91d0d15d000787a80aadb69c7511a7f220f245a29941cbc16dd56d4' 
  AND token = 'FEEXzy96FtNJ+Lxf40MeZimiYdziNXiIhn2FUXRjn6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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