SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23771a249218a813ea7ae57ef751fb0ab72bb25e0bad47fb83bef3a8cb6fd62b' 
  AND token = '4JUdxmAuB/wXc1hQWMHUO22F/YH22F+L/2JlhckY6D8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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