SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '905e65cd19b86271538c1f45a400479f6b3e12b01f4f2d61a6425772bfd9d274' 
  AND token = 'R9Mb3tQMU8Xavf/Z/6LuY1GYRzZxxcpjHx+qI6neNUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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