SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1209793e2fb7398f6a4c447a45127e0f48d41d71bc751d9e3abe2e7661aeb608' 
  AND token = 'd6OQcZTu/73o84hWGuyGSztvZ1HJZkpB6PqsC12g2r4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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