SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '702eaaac094438d82c7e3f6f0bbed2ef2b8063658f3eefbba09e2cd115c9d936' 
  AND token = '4v5AtXhA7YWlHCXLKiDgX5kqKZ3pzi4ZgYjnwspqBbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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