SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '422c8362321d8111cd7361ffab17a7701338028dafa5da7c518b912cfacff650' 
  AND token = 'sHvJ6uShcAvMyM8Wfo7Cs2JiuwZV0ffUqdQJsbZnmnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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