SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '508664b19570882ab82343915b996c495254a0ff4a95651173db9437b239f46f' 
  AND token = 'eOUxxzSy/EskI/fhqZemgVYKU78k0UaGHJBGMFYK8qA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}