SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a76ccbc5aae917da2faee8bcee9beaddc2568475d5adf30c233d6549c4db66eb' 
  AND token = 'hOvuJEV6zkZr0VB1BtbOcJ72lqRYbazWEry6TVOQfn4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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