SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '196aa97917efcd852a3f4ed2efebe1355a5c0742397b0d38ef84f81a54c69c27' 
  AND token = 'rjERZIzsw/TlxZ+DcHWzMWEqT6sTyWiRVx05OKVh/Hw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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