SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b41e9343c3bbe365a24a663dfe92c06c02c7b3e8520a6e4af35453d19158fe8' 
  AND token = '7DzFsDWlLzGvR/uDBORQsgO2TMqDmrPxU+elHJSVFiI=' 
  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"
    }
  }
}