SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3c326f5eec0438a75fa5ce74d6f73d3bcedd88ea2fef9e9fd9727c546623bad' 
  AND token = 'fhkOTFImQmygq1MdnQr6eFMT177LbKcTTjtwh2uieNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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