SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98194e7721eb1292f2a677da8b85215aaa0b47d715228773c7c1a95d65e11f2a' 
  AND token = 'U5vAxa1ShXzs0UB5PzFyxTGsUDMrObXdqE8qV0TzWpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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