SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '350052b92d66b102e74c70c91396e023417c1ea080a7bd0eaa423863311089d8' 
  AND token = 'TSLCrAFDRvTYur+UKrw9KRqQLO279AoFTPK4+IcXYIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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