SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb252ed89db1fbbd6d112a7971de369c5302478a01ef247de33fc6448c563f42' 
  AND token = '21yJThVjigjE+R5wygeSjckhTS9gQB+/uJd0HXIlj8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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