SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6596ccaf56f9741adcd8ee6fbfa692dcfbc91612a9c20ac1ea944de6c655b96a' 
  AND token = 'lJYrezngSeD74BtdD55SFoJxHqGyrWDvA7UUdmk5eAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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