SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92f267aefa934659630147760bc3493776a7062684b580a1b3a835a100e7cb48' 
  AND token = '9KpwwWgzV8jxMg23JUR6slXE9uHACA/t/Bdq9N+WNvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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