SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '367ecf73ac9c21e608b97e46e93edc995c7055fd6e60b4eee5c7ff0cbee3b9d5' 
  AND token = 'rEa1eXFXmidHDRlB9Hf9dEV4fPtv6xak/AAeLoEu/Zs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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