SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b09929a5cf6133a29c95e584c120fe3b994800d734ad261be230db1bffc2187' 
  AND token = 'po8SXBVhd+a7O0R6xrNHL8BKm9zGjbUHjBzZXlroGYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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