SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1981c38b28b4c27369405720c6954c19799f90acc5c3462a4455ef3da966e1a8' 
  AND token = '5z3xRUWSF0JGSmlagzp1eyQhFenCoJYvGSyWnNKLIm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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