SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b05d6b99ec45d0aa8cf40c71dccdd065fb6a566aa794fd79aa00303b08413a2a' 
  AND token = '+BUsy6wQiZm4ak1SGxIM78kgYvEJmJ6Jv+jyZR7SS5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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