SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4f395f6043389cf18bf62167bfb16eef9bbff897c4153d6943196e2440dfa98' 
  AND token = 'fjhz6P16a6BFizFE8P4TsuVkvHAgTy/jpAbM4Sz9F30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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