SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '028b49db2cdd16bc088c6f6f7658784d83831e34fe66c7b458d777949485294f' 
  AND token = 'EpVxlAfKGPga7reNmenq/YT4wULc9KtrwFfwVzfs+JA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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