SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2457b9fd18cf9483a93a5cd1fa478ad113c3bd75528f31e52973780f3c691754' 
  AND token = 'g0O4yF39DUlHxqxZxnhpYI/jqPcfzOzxCAzat/C5BFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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