SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bf69eb0cdb56d1ef24779d67ebc6c13647752b9094d263fc849aa2d30b6f6cf' 
  AND token = 'Xd3OyTjSTUNYCnqekVIAIF+ghDgTCYKLDrQa3QfWD2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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