SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52f358560dd6382bc46610b047ccf88a5c0317094cdbd72f93d6ec659fb6201d' 
  AND token = '9iopsOB0+W2rvoRjuItyZvstmo++DmnW1FlN+JsoK9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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