SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be5271167f0b916a85abc4924cb0a416c38b0d0bdcf27a7f75c76a649f1c52bb' 
  AND token = '9Szj+9kPPnmjclHhfzjVODl17Ip7lZNgslYJsQKbLBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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