SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89c51e37e09ce6f19d43821c1caea09d11cb4f2f7e6ff622a05032ac05dccd28' 
  AND token = 'iRphV8SdKXdQSmFIBBdDFPZ+8eKyofBzh880L9UtAqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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