SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fad8f52198b7d605f587e5dcf59822b96af5e645ff4695e0843993823c8a74e7' 
  AND token = 'H8V3MqwVqS9IDMY6oUnfN4yW/nJa5Zyzus0Xo+1KLZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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