SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7931856a6f0057127b606d546d4d84d5c9a029f6e90fafcb5277e457e508d235' 
  AND token = 'h7co5AZ4txi6pzCsladvqknZfbBLfgTmndJlnlA5krc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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