SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1028ad41509c4f58988fa45e276010d759099b3b663d2bd474af598848e025e' 
  AND token = 'JYQGXoEcXd5gOL2JpzuF7fgjsnBzjulIIhyQiaBUK78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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