SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf864c36c1f703da66268beb974bee394c695b929565311205b7bf80896a16fa' 
  AND token = 'bssUEIG8SAIddqFG9LHUCZPRqOIIycHpihkW5bYLjw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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