SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '165a7477a9683150e38f417f1c46bf5f4ca517cc02f5b8eee6f43c74c371fc32' 
  AND token = '/HkqbrQL+H5jv59migesKhIamB0J+sO5PMSnQaPfFDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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