SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba54f0bd3dd04bc7943b6283f6d9ed02f09c033b67db4253eaf0a4f6dfca2b01' 
  AND token = 'QiMrDypJIXdZWdzngxfDKEYTWUFxBMRQ2qrxZchYvDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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