SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e23e1a92a7a28305f4a85dc194536686206a53bc7b5ee1b924a2ab9b1c21ee01' 
  AND token = 'ioPLC+0mLesTXEAwQrx67pn35eiMyvHpnGbtDCR/RPw=' 
  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"
    }
  }
}