SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '784d10539aaa27f8383d47317cf6f809ee74be664ff196149fb0f08223fb827c' 
  AND token = 'XNj2VTsbEm9wo6iyqNaOS07n65HwmJzclO0pXmElJt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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