SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71b53530f85102605325069f4f7f206ddb482782ac43e70502440a8788b6792f' 
  AND token = 'na4u8x+RSzYYe+sRMphvYnsV6I93Ig/L3DaBJlyAEMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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