SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eaa1db455dc2482574019361be085965dd021ec6ce06d3d2f29857957f4969ea' 
  AND token = 'MfXTWi74WZj93r6mD8/RfBYIRtZYBJccvGczwPzu+Pc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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