SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a72f215167477f4e8298aa692eb1600d95ad7fae059198f473fabbfef0e11b5' 
  AND token = '2JxWK6UmKKjRISdOCCoyc0lr6PvYK8875rRHRv70AHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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