SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b1a1e7c2a870d56fc8785b684aa1912509ce287d87dd9d3ac2dfd2018eaaaac' 
  AND token = 'mtwu/HFHF0SqsF9ZTHPZSJmE3pEUVwh+3ZV4tKUz/Cw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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