SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d349bbb0568c6ae7c8c120bd224ecd4352fbfc520978a21fdfbaec552bd07a6' 
  AND token = 'ud+cnLJhROBvpmZke98V1KIKRxvfBKTa5cgIVouAZ9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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