SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6e9404f719ab342e55f24e046ebf44d5c09109a08854d9bf7ca5592d67985dc' 
  AND token = 'URIq1QxUqreTOqjnoRvFYCybdFG4ajHXIKwuLgNyj/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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