SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '579f53159127a4cc966ac3de78ff46df4c89831d03e579dd0bc08d8a4da0f031' 
  AND token = 'IkMIV3tw53GJuLHkfAlHzW7OmRtJ13Efg7Js/vEtFzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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