SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '520a02bbe55157cd44c992b71a685cd756fcee0f5c58db8b356cdd1453f58a8e' 
  AND token = 'StwSOsBp4MoA5RytOmZjInVYD20dG5NoRidDoKdB7wI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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