SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b0f05ebd8f3a7b04fcdd3edd16901d4d8a72b5e742d1f092465feeabc8ba8d5' 
  AND token = 'ZQi4MnXZcfHKrXriAhEi5Cw8AGx4IG1Y0rQ9L+cnODo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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