SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35bcf11a3d957621969fe720385e82c74d20ed34a6af0bc23946ba907567ab77' 
  AND token = 'CoDZFYUbYts6h1VE7lbOiDcmopkr7UWYkrWFK3KeVDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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