SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3d9816b00c2879eecf2a8ce91043b12712ddeb4f140f658f00f9ce84b09a1c8' 
  AND token = 'gEu21LbHOkxeWBlLWrEifnmPWmkvpWvy1f5FD9e5cSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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