SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd762e558e1507e8474328adcaf26fd9accc7a22b8bc9b2af9f894f69f6750052' 
  AND token = 'AijLNNXP9ElcZgQS2TznVodHOC0X212YvW+8fRL1laM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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