SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfffd4df6e0acca88442272979a5821aa4423349457af393f2ccb7bbbbcfaf42' 
  AND token = 'jjbgAn7el5BV/JTecdCSrlfz+zo9fYAjO0MDhTBlrz4=' 
  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"
    }
  }
}