SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83d83303b07cab22517a4bcb79539432cc5fdbb83226292746989bf21d992e28' 
  AND token = 'qPlF0E1VxS3dosP8lyIyLqVsrENNtiJUGr9zPdR6vq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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