SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2b7e506fae688c42429dda924ab73d51b2fcdd2c6cde36da34bb866825ec397' 
  AND token = 'F8iOtgU5z8wRdDH0nAH/kXb9WdjWbTlSg45wxL8V+7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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