SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c13716c09c5c96ccf6affd28bff73098fca9e54e4492975b1440f71e3489a44b' 
  AND token = 'ChY7qZHq6jFxJnC+f/ieBmrh/o+3l475jRiv04P2nh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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