SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93c7f8fe27b9c221a79a92bb30e9aa682183bd58517eae1ed2fffd5817185b7f' 
  AND token = 'WG6SrrN5Psq57x42vxK4Cn/77yflTYYKrJ4cp/cOFrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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