SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fb43e32b75e0065ad6cde7f1cec9876b4cfef135005a2bc39fcdf933b338854' 
  AND token = 'ux88ofpv3Y7vLpvk4+DwujLEMZbSKoV5gVS9kqxMBWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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