SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a32e86b5cd3a68387b39c284fe10212b74213faba44508255ae2616dbfc2af6' 
  AND token = 'oOY+8MTDUMfBuuYlvQ+upWFF4FWZDLghj+mqrLXVocI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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