SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '719760e3ec63934cfa5479119a1234428436fdae849cd308491a3a6bb3643595' 
  AND token = 'ykZHf/kwmheEH/5Uu8F0SJVCaTL4XTsSjHHyXgSJ35s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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