SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e1e4d4f7e5a421874cce857dcbbe150bacbe1f1353725277c1c84ccd61b9604' 
  AND token = 'oI4S7Y+j3IMpo07eZF8RwynNUhKB7k3O7bToiVUhoOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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