SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd61eb16c53d498058471a35355a8be117c7c6410e8173582270ad9fc394bc10' 
  AND token = 'n/1xG1wWkxNL8NQhurd2fsTy6Nrv6u0YbaFODttNj1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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