SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec7f43de3309a832ce61d746d7eea73ccd8a955841aa0d14b9e85edac3dcb964' 
  AND token = 'Nhjn+atgTmMSvYzipfJ1Ji6z6eVCKbCnwl8Siyb0DlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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