SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de25659fec5333ec07ce31f64b13259c424ad17906b9bbe509fc7a4437639484' 
  AND token = 'd4DdIxm5IaY7zyltvCGVAWwEGk2BEx3xNRqzUR7wrck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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