SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '401948343357cbf2d0802f924f5988ce871090afa5cac47868da8130b3d99323' 
  AND token = 'J8LWkE6wVDIvVNjdiimATBxG6UOwmAOOGtlxabeMknA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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