SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cefa69950393c393562d63b56551785bf0ba4574f43a79c0b4f616a58e6ea38e' 
  AND token = 'ytCc0vtxbdt6xgnbZtn2SaYGRQsj+qkVGOgQbGVCxGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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