SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7d19901215d88804cd7a694b126afffb5039fedcf483fb3528e6ee397c4c20b' 
  AND token = '6M235Hdf78V5RvNOz64mTv+dVLvdsLmjgjEZSYXCgqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}