SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce48f47dac5eff954e423eb5f16345f3daa644632361028268a2dcf9caf6a02b' 
  AND token = 'SQVDdMq+7NODNzBYhIGofqX97ShR33i7pGTVMcA21HQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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